An impact tool disclosed in Japanese Patent Application Publication No. 2002-46078 drives a rotational impact system, with a battery pack as a power source and with a motor as a driving source, so as to give a rotary motion to and an impact on an anvil. The impact tool then intermittently transmits the rotational impact force to an end bit to tighten a screw, and the like. A direct-current motor having a brush and a commutator is known as a motor which has been employed as the driving source. On the other hand, several attempts to employ a brushless direct-current motor instead of the direct-current motor, is also made. Since brushless direct-current motor is more excellent in torque characteristics than the direct-current motor with brush, the impact tool that employs the brushless direct-current motor can tighten a screw, a bolt, or the like, into a workpiece more powerfully.